U.S. Pat. No. 4,882,335 discloses a method for treating alcoholism in which the learned response of alcohol drinking is extinguished by being emitted while the reinforcement from alcohol in the brain is blocked with an opiate antagonist.
The antagonists disclosed for use in the method described in U.S. Pat. No. 4,882,335, however, have various disadvantages. Of the antagonists specifically disclosed, i.e., naloxone, naltrexone, cycloazocine, diprenorphine, etazocine, levalorphan, metazocine, nalorphine and salts thereof, only naloxone and naltrexone are approved for general use. Naloxone cannot be taken orally. Naltrexone can be taken orally but because of a high first-pass metabolism, its oral availability is only 5%. Variability in first-pass metabolism also makes oral dosing with naltrexone less predictable than desired.
Naltrexone is also now considered to be a first-class hepatotoxin. Since alcohol abuse is frequently accompanied by liver damage, the use of naltrexone is counterindicated in patients with alcoholic liver cirrhosis and is questionable in other alcoholics that have not yet developed cirrhosis.
It is an object of the present invention, therefore, to provide a method for treating alcoholism in which the learned response of alcohol drinking is extinguished while the reinforcement from alcohol in the brain is blocked with an opiate antagonist which avoids the disadvantages of the antagonists previously disclosed for such use.
This and other objects and advantages of the present invention are accomplished with the use of the opiate antagonist nalmefene as described hereinafter.